Multi-block sputtering target with interface portions and associated methods and articles

ABSTRACT

A sputtering target that includes at least two consolidated blocks, each block including an alloy including a first metal (e.g., a refractory metal such as molybdenum in an amount greater than about 30 percent by weight) and at least one additional alloying ingredient; and a joint between the at least two consolidated blocks, the joint being prepared free of any microstructure derived from a diffusion bond of an added loose powder. A process for making the target includes hot isostatically pressing (e.g., below a temperature of 1080° C.), consolidated preform blocks that, prior to pressing, have interposed between the consolidated powder metal blocks at least one continuous solid interface portion. The at least one continuous solid interface portion may include a cold spray body, which may be a mass of cold spray deposited powders on a surface a block, a sintered preform, a compacted powder body (e.g., a tile), or any combination thereof.

CLAIM OF BENEFIT OF FILING DATE

The present application claims the benefit of the filing date of U.S.Application Ser. No. 61/644,669 filed May 9, 2012, the contents of whichare expressly incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to sputtering, and moreparticularly to improved multi-component sputtering targets and theirmanufacture and use to produce thin films that include a plurality ofblocks joined together during a consolidation operation (such as a hotisostatically pressing operation), which avoids diffusion bonding ofloose powder, to define at least one interface portion.

BACKGROUND OF THE INVENTION

Sputtering processes are employed to deposit thin films onto substratesto manufacture any of a variety of devices. Sputtering processestypically involve bombarding a solid sputtering target with energizedparticles to eject atoms from the target. In recent years, there hasbeen a growing need for large area sputtering targets. This isespecially so for certain applications in which large sized products aremade. For example, flat panel displays often require the deposition ofuniform thin films onto a substrate. The demand for larger displays,such as for televisions, continues to strain materials producers todevelop alternative approaches to the efficient supply of suchmaterials.

In one specific application, according to U.S. Pat. No. 7,336,324 (Kimet al), the deposition of a molybdenum titanium barrier layer onto asubstrate has been employed for the manufacture of a liquid crystaldisplay device. Such application intensifies the need for large displaydevices capable of delivering such materials, particularly targets thatcontain both molybdenum and titanium.

In the manufacture of large area sputtering targets it is often deemedcritical and imperative that the target exhibit uniformity incomposition, microstructure, or a combination of both. For some devicemanufacturers that rely upon the targets to manufacture devices, theslightest imperfections are perceived as a potential quality controlrisk. By way of example, one concern for manufacturers is the potentialformation of particles (e.g., atomic clusters or aggregates having anatomic composition different than the atomic composition of otherregions of the film) during device manufacture. U.S. Pat. No. 6,755,948(Fukuyo et al) discusses the potential effects of particles in thecontext of titanium targets.

Activities in the sputtering target field are illustrated by referenceto a number of patent filings. By way of illustration, U.S. PatentApplication No. 20070089984 describes the formation of a large areasputtering target by the use of a powder between cold-isostaticallypressed blocks of a mixture of molybdenum and titanium powders. The useof such powder generally results in the formation of a conspicuous bondline between adjoining blocks. Even if such bond line does not actuallyadversely affect performance, its conspicuous nature is a potentialconcern for device manufacturers. For instance, some manufacturers havethe perception that the bond line may contribute to the formation ofundesired particles during sputtering; if generated, there is a beliefthat such particles potentially might affect performance of resultingdevices. U.S. Pat. No. 4,594,219 (Hostatter et al) addressesside-by-side consolidation of preforms to form complex or compoundshaped articles (e.g., connecting rods and hand wrenches). Consolidation(e.g., by hot isostatic pressing) of molybdenum and/or titanium powdercontaining preforms is not described. Moreover, particular processingsteps to achieve successful results in the consolidation of molybdenumand/or titanium powder containing preforms is also not described.

U.S. Patent Application No. 20050191202 (Iwasaki et al) discloses amolybdenum sputtering target (in which an example is provided of a 70.0at % Mo-30.0 at/% Ti material). The application discloses a requirementfor use of relatively high temperatures and pressures, stating atparagraph 40 that if a pressure below 100 MPa and a temperature below1000° C. is used, “it is hard to produce the sintered body having arelative density of not less than 98%”. The application describes aprocess by which a relatively large size body is consolidated fromsecondary powders and then the sintered body is out into separatetargets. One example illustrates a further hot plastic working step.

U.S. Patent Application Publication 20050189401 (Butzer) discloses amethod of making a large Mo billet or bar for a sputtering targetwherein two or more bodies comprising Mo are placed adjacent one another(e.g. stacked one on the other) with Mo powder metal present at gaps orjoints between the adjacent bodies. The adjacent bodies are hotisostatically pressed to form a diffusion bond at each of themetal-to-Mo powder layer-to-metal joint between adjacent bodies to forma billet or bar that can be machined or otherwise formed to provide alarge sputtering target. This patent publication appears to disclosebonding of major side surfaces, not edge-to-edge bonding of plates.

U.S. Patent Application No. 20080216602 (Zimmerman at al) describesanother method for making large area sputtering targets with amolybdenum-titanium composition, which includes a cold spray depositionstep for joining a plurality of targets at an interface. Thoughacknowledging certain electron beam welding and hot isostatic pressingprocesses to join targets, in paragraphs 165-166 (referring to FIGS. 17and 18), the patent application indicates that electron beam weldingresults in porosity, and the hot isostatic pressing results in a brittlealloy phase.

U.S. Patent Application No. 20070251820 (Nitta et al) descries anexample of another approach to the manufacture of a molybdenum-titaniumsputtering target. In this publication, diffusion joining (at atemperature of at least 1000° C.) of two or more previously sintered ormelted sputter targets along at least one side is addressed. The use ofa Mo—Ti powder in the joint is described.

U.S. Patent Application No. 20070289864 (Zhifei et al) identifies a needin large area sputtering targets to fill gaps between multiple targetsections carried on a common backing plate. The patent illustrates thematerial deposition processes between adjoining target portions.Interestingly, the patent recognizes that the manufacture of largemolybdenum plate targets poses difficulties, and the need for efficientmanufacturing.

Cold spray technology is an approach that has been employed to deposit apowder material onto a substrate in the absence of heating the powdermaterials. The use of cold spray processes in the field of sputteringtargets is illustrated in United States Patent Application Nos.20080216602; 20100086800; 20110303535; and U.S. Pat. No. 7,910,051, allincorporated by reference herein for all purposes.

The formation of multi-component large scale sputtering targets thatinclude molybdenum and at least one additional alloying element istaught in commonly owned U.S. Provisional Application Ser. No.61/464,450 filed on May 10, 2011, and Ser. No. 13/467,323 filed on May9, 2012, and also PCT Publication No. WO 2012/154817, each incorporatedby reference herein for all purposes.

In view of the above, there remains a need in the art for alternativesputtering targets (especially large size targets, such as targetsexceeding about 0.5 meters, about 1 meter, or even about 2 meters forits largest dimension), and approaches to their manufacture that meetone or any combination of the needs for general uniformity ofcomposition, general uniformity of microstructure, insubstantiallikelihood of particle formation, or relatively high strength (e.g.,relatively high transverse rupture strength). Moreover, there remains aneed in the art for alternative sputtering targets that avoid the needfor powder during any final hot isostatic pressing process. Forinstance, it may be desirable that any added material that will becomepart of a joint between adjoining blocks is a generally solid andcohesive mass of material prior to a final consolidation (e.g., by a hotisostatic pressing operation). The ability to minimize any visible jointlines or other visible variations in continuity of structure, though notcritical for resent purposes, may also be a desirable attribute.

SUMMARY OF THE INVENTION

In one aspect, the present teachings meet one of the above needs byproviding a sputtering target, which may in particular be a relativelylarge sputtering target (e.g., exceeding about 0.5 meters, about 1meter, or even about 2 meters for its largest dimension; or stated inanother way, exceeding about 0.3 square meters (m²), 0.5 m², 1 m², oreven 2 m² for the target sputtering surface available for sputtering),comprising at least two consolidated blocks, each block including analloy including a first metal (e.g., a refractory metal such asmolybdenum, which may be present in an amount greater than about 30percent by weight) and at least one additional alloying element at leastone continuous solid interface portion; and a joint between the at leasttwo consolidated blocks, which joins the blocks together to define atarget body. The joint may include at least one continuous solidinterface portion (which desirably may be a generally coherent metallicmass, such as one that is formed in situ from a particulated startingmaterial (e.g., such as by cold spray deposition of a metallic powdermixture), one that is formed in a separate densification operation(e.g., compacting, sintering or both), or both). Desirably, thesputtering target along the joint will, also exhibit a transverserupture strength per ASTM B528-10, of at least about 400 MPa.

In another aspect, the teachings herein meet one or more of the aboveneeds by providing a method for making a sputtering target, comprisingthe steps of providing first and second at least partially consolidatedpowder metal blocks each optionally having a prepared surface, and eachincluding an alloy including a first metal (e.g., a refractory metalsuch as molybdenum, which may be present in an amount greater than about30 percent by weight), and at least one additional alloying element,interposing between the consolidated powder metal blocks at least onecontinuous solid interface portion (e.g. before a final consolidatingstep); contacting the prepared surface of the first block indirectlywith the prepared surface of the second block via the at least onecontinuous solid interface portion in the substantial absence of anybonding agent between the contacted surfaces to form a contacted jointstructure; isostatically pressing the contacted structure at atemperature (e.g., one that is less than about 1080° C.), at a pressureand for a time sufficient to realize a consolidated joint between thefirst and second blocks.

The continuous solid interface portion may be formed in the absence ofapplying powder between blocks prior to a joining step; namely the stepsof manufacture would avoid any loose powder between blocks to accomplishdiffusion bonding during a hot isostatic pressing step that results inthe formation of a target body, such as a lame scale target body, whichincludes the blocks. The continuous solid interface portion may beformed by employing a step selected from (a) cold spraying a metalpowder onto at least one of the blocks for forming the at least onecontinuous solid interface portion (e.g., along a side edge of one ormore blocks); (b) compacting a body of metal powder (e.g., a metalpowder admixture) to form the at least one continuous solid interfaceportion (which is thereafter interposed between blocks); (c) sintering abody of a metal powder mixture to form the at least one continuous solidinterface portion (which is thereafter interposed between blocks); (d)cold spraying a metal powder into a die for forming the at least onecontinuous solid interface portion; (e) cold spraying a metal powderonto a substrate to form the at least one continuous solid interfaceportion that may optionally include, but preferably omits, thesubstrate; or (f) any combination of (a) through (e). The continuoussolid interface portion thus may be the result of employing a cohesivemass that is formed in situ with metal powder blocks (e.g., by a coldspraying operation) or is formed as a preform (e.g., a tile that iscompacted, sintered, and/or cold sprayed, and is thereafter interposedbetween blocks). Though the cohesive mass is contemplated to have someporosity, desirably the average size of any pores is sufficiently smalland the pores are substantially uniformly distributed so that voidswould not result in irregular shrinkage in a consolidated jointfollowing a final consolidating step to make a large area target.

In general, when a mixture of molybdenum and titanium is employed tomake the continuous solid interface portion, conditions may be employedso that prior to any final consolidating step, the amount of uncombinedtitanium remains generally high. For example, the amount of startingtitanium powder in the mixture that remains unalloyed prior to a finalconsolidating step to form a resulting target is at least 50%, 60%, 70%,80%, 90% or more weight of the total titanium in the mixture. Thus, thestep of forming any continuous solid interface portion precursor (e.g.,a cold sprayed mass, a tile, a sintered body or any combination thereof)may be done at a temperature below the melting point of titanium. Ifsteps are performed above the melting point of titanium in the mixture,then they are performed for a time sufficient for avoiding alloyformation with other metals in the mixture by which less than about 50%,40%, 30%, 20%, or even 10% by weight of the starting titanium in thepowder mixture becomes alloyed with another metal in the powder mixture.

The target bodies in accordance with the teachings herein may have aVickers Hardness (HVN) per ASTM E384-06 of at least about 260, about 275or even about 300; for example, it may have an HVN of about 260 to about325. The target, the target body, the alloy, one or more consolidatedblocks, or any combination thereof may include molybdenum in an amountgreater than about 30 weight percent. The target, the target body, thealloy, one or more consolidated blocks, or any combination thereof mayinclude molybdenum in an amount greater than about 30 atomic percent.The target, the target body, the alloy, the consolidated blocks, or anycombination thereof preferably may include molybdenum in an amountgreater than about 30 volume percent. The target body may have a densityof at least about 0.92, 0.95 or even 0.98 times the theoretical densityof the overall material per ASTM B311-08. For one illustrative targetthat consists essentially of molybdenum and titanium, the target bodymay have a density in the range of about 7.12 to about 7.30, and morespecifically about 7.20 to about 7.25 g/cm³. The sputtering target bodymay also be sufficiently strong so that it withstands, without fracture,routine stresses encountered during subsequent assembly operations(e.g., a three point straightening assembly operation, a creepflattening operation, or some other operation during which the targetbody and any joint may be subjected to a load of greater than about 0.6MPa).

In yet another aspect of the teachings herein, it is contemplated thatsputtering is performed using a sputtering target in accordance with thepresent teachings. It also is contemplated that thin films result thatare used in any of a number of electronic devices (e.g., as a barrierlayer, an electrode layer or both), such as one or more of a television,a video display, a smartphone, a tablet computer, a personal digitalassistant, a navigation device, a sensor a portable entertainment device(e.g., video players, music players, etc.), or even a photovoltaicdevice. The thin films may have a reduced amount of structural artifactsattributable to particles as compared with sputtering using targets madewith powder joints.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a cold spray joint preparation.

FIG. 2 is an illustration a cold spray formation of a tile.

FIG. 3 is an exploded perspective view of a block-tile-block structure.

FIG. 4 is an illustrative scanning electron a microscope backscatterphotomicrograph at 500× for illustrating phase amounts that may beexpected in a hot isostatically pressed target made from a mixture of 50at % molybdenum and 50 at % titanium powders.

DETAILED DESCRIPTION

Turning now in more detail to particular teachings of the presentinvention, in general, the present teachings envision a relatively largesputtering target, and particularly a sputtering target consolidatedfrom metal powder, wherein the target is made by joining multiple blocksin the absence of a powder interface. The target generally will includea target body (namely, the consolidated portion of the target, andspecifically the portion of the overall target assembly that issubjected to bombardment for purposes of material removal and sputterdeposition) that may be joined to a backing plate in any suitable artdisclosed manner. The sputtering target body may be any suitablegeometry. It may be generally circular (so that it would have a diameteras its largest dimension). It may be rectangular, and thus have one ofits side edges as having its largest dimension (e.g., the length of theside edge). It may be tubular. Though the teachings herein also apply tosmaller sputtering targets, they have particular utility for largerscale targets. By way of example, larger scale target bodies may besized such that they exceed about 0.5 meters, about 1 meter, or evenabout 2 meters for its largest dimension. Examples of such target bodiesmay be generally rectangular targets having a length that exceeds about0.5 meters, about 1 meter, or even about 2 meters. Such target bodiesmay have a width that exceeds about 0.5 meters, about 1 meter, or evenabout 2 meters. The resulting target bodies may exceed about 0.3 squaremeters (m²), 0.5 m², 1 m², or even 2 m² for the target sputteringsurface available for sputtering.

The target body is typically made to include at least two consolidatedpreformed blocks, and a consolidated joint portion, which preferably maybe a continuous solid interface portion, therebetween. The consolidatedblocks will typically be sized (e.g., length, width, area, or anycombination thereof) to be smaller than the overall resulting targetbody. For example, they may be about one half (or smaller) the size(e.g., length, width, or area) of the desired resulting target body(e.g., they may be about 1/n the size of the desired resulting targetbody, wherein n refers to the total number of consolidated blocksemployed to make the target body, exclusive of any intermediate tiles asdescribed herein). Each of the consolidated blocks may each beapproximately the same size as each other block. One or moreconsolidated block may be smaller than another other blocks. The blocksmay be of generally the same shape as each other, or they may differ asto shape. The blocks may have a generally rectangular prism shape. Theblocks may be generally cylindrical. The blocks may include one or morechannels, through holes or other openings. For example, the blocks maybe generally cylindrical and have a through passage for defining atubular shaped block. One or more side walls of the block may begenerally orthogonally oriented relative to a surface that will functionas a sputtering surface. One or more side walls of the block may begenerally oriented at a slope angle of at least ±5°, 10°, 20° or morerelative to a plane that would be perpendicular to a sputtering surface.In this manner it is possible that a joint may employ a scarf jointbetween adjoining blocks. Other joint structures other than a butt jointor a scarf joint may be employed, such as a lap joint, dovetail joint,or any combination of the above joints.

More particularly, a plurality of blocks are prepared by consolidatingpowdered metal. The consolidation may occur from sintering, coldisostatic pressing, hot isostatic pressing, otherwise compacting (e.g.,rolling, die compacting or both) or any combination thereof. Forexample, one approach is to first compact to about 60 to about 85% oftheoretical density, such as by cold isostatically pressing a mass ofpowders of the desired composition (such as is taught in U.S. PatentApplication No. 20070089984 at paragraph 50 through 53, incorporatedherein by reference (Gaydos et al)). The resulting compacted forms maybe machined to form block precursor structures. The blocks (or blockprecursor structures) may be further densified such as by hotisostatically pressing to form blocks that will be joined with others toform a target body. It is contemplated that the powdered metal, beforeconsolidation, will include one or more powders of a substantially puremetal (e.g., having a purity (defined to mean free of metallic elements)of at least about 99.5%, 99.95% or even 99.995% purity).

The powders, before consolidation, will typically have an averageparticle size of less than about 50 μm, or even less than about 35 μm,as measured according to ASTM B822-10. For example molybdenum powders,before consolidation will typically have an average particle size ofless than about 25 μm, or even less than about 5 μm, as measuredaccording to ASTM B822-10. When titanium is employed, the titaniumpowders may have an average particle size of less than about 50 μm, oreven less than about 35 μm. The titanium powders may have an averageparticle size of higher than about 5 μm, or even higher than about 25μm.

Prior to consolidation, powders may be blended in accordance with artdisclosed powder blending techniques. For example, mixing may occur byplacing the molybdenum and titanium powders in a dry container androtating the container about its central axis. Mixing is continued for aperiod of time sufficient to result in a completely blended anduniformly distributed powder. A ball mill or similar apparatus (e.g.,rotating cylindrical, rotating cone, double cone, twin shell, doubleplanetary, and/or sigma-blade blender) may also be used to accomplishthe blending step. As discussed herein, and unless otherwise stated,references to metal powders include powders of one metal or acombination of two or more metals.

The composition in each block of the resulting target body willgenerally include molybdenum and at least one additional alloyingelement. For example, the composition may include an alloy includingmolybdenum in an amount so that in resulting target body there is asubstantially pure phase of molybdenum present in an amount greater thanabout 30 vol %, greater than about 35 vol %, or even greater than about40 vol % of the resulting target body, and at least one additionalalloying ingredient. The composition may include an alloy includingmolybdenum in an amount so that in the resulting target body there is asubstantially pure phase of molybdenum present in an amount less thanabout 48 percent by weight, or even less than about 45 percent by weight(e.g., about 43 percent by weight) of the overall block, and at leastone additional alloying ingredient. The amount of the molybdenum in thetarget, the alloy, or both, may range from about 5 to about 95 at %,more preferably about 20 to about 80 at %, still more preferably about30 to about 70 at %. It may be about 40 to about 60 at % (e.g., about 50at %). The remaining alloying elements may make up the balance. Forexample, the amount of titanium in a system employing only molybdenumand the additional alloying element powder may be about 100 at % minusthe amount (in at %) of molybdenum. Thus, as can be seen from the above,the teachings contemplate a composition of the target, the alloy, orboth, of about 30 to about 70 at % Mo and the balance being the at leastone additional alloying element such as titanium (e.g., about 50 at % Moand about 50 at % of another element (such as titanium)).

In general, when a mixture of molybdenum and titanium is employed tomake the continuous solid interface portion, conditions may be employedso that prior to any final consolidating step, the amount of uncombinedtitanium for use as a continuous solid interface to define theconsolidated joint portion remains generally high. For example, theamount of starting titanium powder in the mixture that remains unalloyedprior to a final consolidating step to form a resulting target is atleast 50%, 60%, 70%, 80%, 90% for by weight of the titanium in themixture. Thus, the step of forming any continuous solid interfaceportion precursor (e.g., a cold sprayed mass, a tile, a sintered body orany combination thereof) may be done at a temperature below the meltingpoint of titanium. If steps are performed above the melting point oftitanium in the mixture, then they are performed for a time sufficientfor avoiding alloy formation with other metals in the mixture by whichless than about 50%, 40%, 30%, 20%, or even 10% by weight of thestarting titanium in the powder mixture becomes alloyed with anothertall in the powder mixture.

The at least one additional alloying element may be a metallic element,such as one selected from titanium, chromium, niobium, zirconium,tantalum, tungsten or any combination thereof. It is possible that theat least one additional alloying element may include hafnium and/orvanadium. It is also possible that the at least one additional alloyingelement may include one or more alkali metal (e.g., lithium, sodiumand/or potassium in an amount of less than about 10 at % or even 5 at %of the total composition). Examples of suitable alloying ingredients aredisclosed in PCT Application No, WO2009/134771, and U.S. applicationSer. Nos. 12/990,084; 12/827,550 and 12/827,562 (all incorporated byreference). The amount of the at least one additional alloyingingredient may be such that it will result in (i) a substantially purephase of that alloying element; and/or (ii) an alloy phase that includesmolybdenum and the at least one alloying element. By way of example, theamount of the at least one additional alloying element may be sufficientto obtain a substantially pure phase of the at least one additionalalloying element that is at least about 2, 4 or even about 6 vol % ofthe resulting target body. The amount of the at least one additionalalloying element may be sufficient to obtain a substantially pure phaseof the at least one additional alloying element that is less than about25 vol %, 15 vol % or even about 10 vol % of the resulting target (e.g.,the resulting target body).

The amount of each of the molybdenum and the at least one additionalalloying element may be sufficient to realize in the resulting targetbody an alloy phase (i.e., one that includes both molybdenum and the atleast one additional alloying element) in an amount greater than about30 vol %, 40 vol %, 44 vol % or even about 48 vol %. For example, thealloy may be present as a major constituent of the block, by volume. Theamount of each of the molybdenum and the at least one additionalalloying element may be sufficient to realize in the resulting targetbody an alloy phase that includes both molybdenum and the at least oneadditional alloying element in an amount less than about 70 vol %, 60vol %, 56 vol % or even about 52 vol %. As can be seen, the alloy phasemay be present as a major constituent of the block, by volume.

The resulting target body may be further characterized by at least one,preferably a combination of at least two features, more preferably acombination of at least three features, still more preferably acombination of at least four features, and even still more preferably acombination of all features selected from the following features (i)through (v); (i) at least one joint between at least two consolidatedblocks (e.g., side-by-side or end-to-end adjoining blocks) that is freeof microstructure derived from diffusion bonding an added loose powderbonding agent; (ii) at least one joint between at least two consolidatedblocks (e.g., side-by-side (such as face-to-face) or end-to-endadjoining blocks); (iii) a sputtering target body that is at least about0.5 meters, about 1 meter, or even about 2 meters, along its largestdimension, and which exhibits a transverse rupture strength per ASTM8528-10 that is generally uniform (e.g., the fluctuation from low tohigh is less than about 50% the highest value, or even less than about35% of the highest value) throughout the body, including across thejoint, and/or which may be at least about 400 MPa, 500 MPa, 600 MPa, 700MPa, 800 MPa or even 900 MPa; (iv) the target body exhibits a VickersHardness (HVN) of at least about 260, about 275 or even about 300 (e.g.,it may have an HVN of about 260 to about 325); or (v) the target bodymay have a density of at least about 0.92, about 0.95 or even about 0.98times the theoretical density of the overall material (e.g., for atarget body that consists essentially of molybdenum and titanium, thetarget body may have a density in the range of about 7.12 to about 7.30,and more specifically about 7.20 to about 7.25 g/cm³). The sputteringtarget body may also be sufficiently strong so that it withstands,without fracture, routine stresses encountered during subsequentassembly operations (e.g., a three point straightening assemblyoperation, a creep flattening operation, or some other operation) duringwhich the target body and any joint may be subjected to a load ofgreater than about 0.6 MPa. Methods herein thus may include one or moresteps of performing an assembly operation (e.g., an assembly operationselected from a three point straightening operation, a creep flatteningoperation, or both). As discussed previously, another aspect of thepresent teachings, which is believed to result in sputter target bodiesthat exhibit one or more of the features discussed previously in thisparagraph pertains to methods for making a sputtering target. Broadlystated, the methods include steps of consolidating at least two blocksinto preforms, and joining the blocks together. The joining of theblocks is desirably done under heat and pressure, and in a manner thatotherwise avoids the need for reliance upon an intermediate powderbonding agent between opposing surfaces of the blocks as a primary modeof assuring a bond between the blocks.

Desirably, the bonding of adjoining blocks relies mainly upon theformation of at least some metallic bonds (with some mechanical bondingbeing possible as well) between metal from opposing cold-sprayedsurfaces of the blocks, opposing surfaces of a block and a preform tile(e.g., a previously sintered and/or a die-compacted tile, which itselfmay be formed by cold-spraying, may include a cold sprayed surface, orboth), or any combination of the above.

Accordingly, one approach involves a step of making a plurality ofconsolidated blocks as preforms. The preforms may have substantially thesame composition as each other. The preforms may be made in asubstantially identical manner as each other. The preforms may beconsolidated in any suitable manner. The blocks of the preforms may beany suitable geometry. For example, they may be generally rectangularprisms. They may be generally cylindrical. They may be hollow (e.g.,tubular). Other shapes are also possible.

Typically the manufacture of the blocks will employ a powder startingmaterial. The powder may be densified by the application for a desiredperiod of time of heat, pressure or both. For example, they may becompacted, sintered, cold isostatically pressed, hot isostaticallypressed or any combination thereof. An initial compaction step mayoccur. For example, an initial step may be employed to compact a mass ofpowder to about 50 to about 85% of theoretical density (e.g., about 60to about 70% of theoretical density). This may be done by a suitablecold isostatic pressing operation. One or more secondary operations mayalso be performed, such as a cold working step, a hot working step orotherwise.

A preferred approach to consolidation includes a step of hotisostatically pressing (HIP) a mass (e.g., an uncompacted powder mass ora compacted powder mass) at a pressure of at least about 100 MPa. Forexample, with molybdenum-containing materials (as well as others), theHIP process desirably may be performed at a temperature below about1080° C. (e.g., at about 1050° C.), 1000° C., 950° C., 900° C., or evenbelow about 850° C. (e.g., at about 825° C.). The HIP process may rangein duration from about 1 to about 12 hours, and more preferably about 4or 6 to about 10 hours (e.g., about 8 hours). By way of example, withoutlimitation, the mass may be pressed to generally rectangular blockshaving a thickness of about 10 mm to about 60 mm, and more preferablyabout 15 mm to about 45 mm (e.g., about 16 mm, about 25 mm, about 35 mmor even about 45 mm). The mass may be pressed into a generallyrectangular block having a width of about 25 to about 100 mm (e.g.,about 30 mm, about 50 mm or even about 90 mm), and more preferably fromabout 30 mm to about 50 mm. The mass may be pressed into a generallyrectangular block having a length of about 70 mm to about 160 mm, andmore preferably about 90 mm to about 150 mm (e.g., about 90 mm, about120 mm, or even about 150 mm).

Two, three, or more blocks are joined to form a target body. Asmentioned, preferably this is done in without employing a loose powderbonding agent as the primary means of joining. For example, though someamounts of a bonding agent may be employed, aspects of the presentteachings contemplate that the joining, to make the target body, may beachieved in the absence of any bonding agent (e.g., absence of any loosepowder bonding agent). By way of illustration, two blocks may beprepared, each having dimensions of about 1.5 meters long by about 0.9meters wide by about 0.16 meters thick. They may be joined togetheralong opposing width edges (e.g., with a continuous solid interfaceportion therebetween) to form a target body. In another illustration,two blocks may be prepared, each having dimensions of about 1.2 meterslong by about 0.5 meters wide by about 0.46 meters thick. They arejoined together along opposing length edges to form a target body. Instill another illustration, two blocks may be prepared, each havingdimensions of about 1.2 meters long by about 0.5 meters wide by about0.3 meters thick. They are joined together, with at least one continuoussolid interface portion therebetween, along opposing length edges toform a target body. In still yet another illustration, three blocks maybe prepared, each having dimensions of about 0.9 meters long by about0.3 meters wide by about 0.25 meters thick. They are joined togetheralong opposing length edges with at least one continuous solid interfaceportion therebetween, to form a target body. More than three blocks canbe employed, such as an array of two or more blocks along two or moreaxes.

Following the pressing, but prior to the joining of the preform blocksto form a sputter target body, one or more surfaces of the preformblocks may be surface prepared (e.g., surface roughened and/or polished,whether chemically, mechanically, electrochemically, a combinationthereof or otherwise) to impart a desired surface finish, such as forincreasing surface area of the surface for contacting an adjoining blockas compared with a surface that is not surface prepared, or forotherwise increasing contact area between two or more adjoining blocks.For example, surfaces that are to oppose each other when joineddesirably are prepared (e.g., roughened). They may be prepared so as toachieve an arithmetic average surface roughness R_(A) (as measured byASTM 8946-06) that may be at least about 50 μ-in (1.3 μm), or even atleast about 100 μ-in (2.6 μm) (e.g., about 120 μ-in (3 μm) to about 150μ-in (3.8 μm)). They may be prepared so as to achieve an arithmeticaverage surface roughness R_(A) (as measured by ASTM 8946-06) that maybe less than about 200 μ-in (5.1 μm), less than at least about 180 μ-in(4.6 μm), or even less than about 150 μ-in (3.8 μm), or even less thanabout 120 μ-in (3 μm). For example, the arithmetic average surfaceroughness R_(A) (as measured by ASTM 8946-06) may range from about 50μ-in (1.3 μm) to about 150 μ-in (3.8 μm)), and more specifically about63 μ-in (1.6 μm) to about 125 μ-in (about 3.2 μm).

One possible approach to achieving a desired surface finish is tocold-spray deposit powders onto at least one surface of a consolidatedblock to the desired roughness. This may be done with or without a stepof surface roughening prior to the cold spray deposition. It iscontemplated that any step of cold spraying may include depositing amixture of powders of at least two different unalloyed metals onto aside of at least one of the consolidated blocks to define the at leastone continuous solid interface portion for causing the powders tomechanically attach to the block, while generally avoiding the presenceof loose powders. Illustrative cold spray teachings can be found inUnited States Patent Application Nos. 20080216602; 20100086800;20110303535; and U.S. Pat. No. 7,910,051, all incorporated by referenceherein for all purposes. In general a suitable device having a nozzle(e.g., a cold spray gun) ejects a powder mixture jet at supersonic speedto direct the powder mixture onto a surface. It will be appreciated that“cold spray” does not exclude other kinetic spray systems. The term coldspray is used throughout the teachings herein. However, it is understoodthat it is possible to use a kinetic spray process as well.

A gas jet flowing at supersonic speed is imparted upon a mass of powder,which may have a particle size of 0.5 to 150 μm. For example, asufficient gas flow is applied to help ensure a velocity of the powderin the resulting gas/powder mixture of 300 to 2,000 m/s, preferably 300to 1,200 m/s. The mixture is directed on to the surface an object. Onthe surface of the object, the impinging metal powder particles form alayer, the particles becoming severely deformed, but preferably are notmelted. The powder particles are advantageously present in the jet in anamount which ensures a flow rate density of the particles of from 0.01to 200 g/s cm², preferably 0.01 to 100 g/s m², very preferably 0.01 g/scm² to 20 g/s cm², or most preferred from 0.05 g/s cm² to 17 g/s cm².

After any surface preparation (e.g., surface roughening, cleaning suchas by a step of detergent cleaning, or both), at least one surface of afirst block is contacted, in the absence of any intermediate loosepowder, with at least one surface of a second block to form a contactedjoint structure. The contacting may be direct, such as by contactingopposing cold-sprayed surfaces of a plurality of blocks. The contactingmay be indirect, such as via an interface preform as described herein(e.g., a tile having a side surface that has generally the samedimensions as the block surface to which it will be contacting, andhaving a thickness of at least about 2 mm, 4 mm or even 6 mm). Thethickness may be about 20 mm or less, or even about 10 mm or less. Thepreform itself may include a cold sprayed side surface for contacting.

When a cold sprayed powder layer is deposited onto a surface of a block,an interface preform (e.g., a tile), or both, the average thickness ofthe layer may be greater than about 1, 2, 5, 10, 50, 100 μm or larger;the cold sprayed powder layer may be deposited to have an averagethickness of the layer of less than about 1 cm, 1 mm, 500 μm, or 200 μm.

The interface preform (e.g., tile) may be made by a process capable ofachieving a density of the preform of at least about 60% theoretical,70% theoretical or even 80% theoretical. By way of example, conditionsmay be such (e.g., sufficient pressure may be applied to the powderduring compaction) to define the interface preform as a the having adensity of about 65% to about 85% of theoretical density throughout thetile, and more specifically about 75% to about 85% of theoreticaldensity. The interface preform (e.g., tile) may have a thickness ofabout 2 to about 10 mm (e.g., about 3 to about 7 mm, or morespecifically about 4 to about 6 mm). Larger or smaller thicknesses arealso contemplated.

Though cold isostatic pressing is one possibility, surprisingly,die-compacting a powder mixture is believed to yield excellent resultsas well. It is also possible that a powder mixture can be cold-sprayedinto a cavity of a die or other suitable tool to define a preform havingthe general complementary shape of the tool cavity. As to the latter itis possible that prior to deposition, the tool is contacted with asuitable low friction coating to aid in removal of the preform in latersteps. The interface preform may be configured with one or moreprojections or other structural feature to allow gripping for removal.The tool may be configured with one or more devices for ejecting thepart from the cavity.

One approach is to make an interface preform such as a tile by diecompacting a mixture of two or more high purity (e.g., at least 99.5%pure, in relation to metallic impurities) metal powders. A suitablepressure is applied (e.g., at about room temperature, and optionally atan elevated temperature), for a suitable time to achieve a near netshape green compact that has a density of at least about 60, 70 or 80%of theoretical density (e.g., to about 60% to about 85% of theoreticaldensity). By way of example, a pressure of at least about 60 ksi, 70 ksior 80 ksi (e.g., on the order of about 1250 tons over about 30 squareinches) may be employed. A pressure of less than about 200 ksi, 150 ksior 100 ksi may be employed. The pressure may be applied for a time of atleast 10 seconds, 15 seconds, 20 seconds or 30 seconds. The pressure maybe employed for a time of less than 5 minutes, less than 3 minutes oreven less than one minute.

Another possible approach to making an interface preform may employsteps that result in a loosely sintered preform, such as a tile. Thatis, sintering may be employed at a temperature and time sufficient for amass of metal powder to density sufficiently so that a cohesive andself-supporting mass is formed that can be readily handled and is freeof loose powder. The preform may be made by mixing a mass of metalpowder (which may include powders of one, two or more metals). A bindermay be included within the resulting mixture. The mass of powder withthe binder may be spread to a generally uniform thickness and sintered.The selection of the binder and the temperatures and times of sinteringmay be such that, during sintering, the binder is consumed and resultsin a certain amount of porosity. For example, a polymeric binder may beemployed. Sintering may be employed at a temperature and time sufficientfor the mass of metal powder to realize at least about 50%, 60%, 70%, oreven 80% of theoretical density. Sintering may be employed at atemperature and time sufficient for the mass of metal powder to densifyto less than about 95%, 90% or even 85% theoretical density. Thesintering may be performed under evacuated conditions. The sintering maybe performed under an inert atmosphere or under a reducing atmosphere.The sintering atmosphere may be free of hydrogen.

Another approach is to make an interface preform such as a tile by coldspraying a powder mixture onto both sides of a thin sheet that includesmolybdenum and at least one other element (e.g., Ti). The cold sprayedpowder layer may be deposited to have an average thickness of the layerof less than about 1 cm, 1 mm, 500 μm, or 200 μm.

It is also possible to cold spray a powder mixture onto a sacrificial ordisposable substrate (e.g., brass sheet, zinc sheet, or galvanized steelsheet) to make an interface preform such as a tile. Instead of preparingthe substrate as is typically done using such methods as a grit blastingstep, it is also possible to prepare the substrate with a detergentcleaning step to avoid embedding ceramic grit particles in the substratesurface. Detergents based on dipropylene glycol methyl ether may beemployed to clean the substrate, followed by a water rinse withdistilled deionized water until the surface passes the “Standard TestMethod for Hydrophobic Surface Films by the Water-Break Test” per ASTMF22-02 (2007). Following detergent cleaning step, the substrate can becold sprayed in successive layers, preferably of greater then about 50μm and less than about 250 μm per pass, to build a cold spray depositwith a preferable total thickness of greater than about 1.5 mm and lessthan about 2 mm. Each pass may be performed under the same or variedconditions. Preferably, the first pass may be performed at high densityconditions to achieve greater adhesion (e.g., increased gas velocity andincreased pressure from the nozzle through which the metal powdermixture is emitted). To achieve less than full density on successivepasses, the gas velocity can be reduced. Following the cold sprayapplication, a relatively smooth surface of the deposit is desired;however, some porosity is also desirable throughout the body of the coldspray deposit to allow for creep or movement during the hot isostaticpressing process. Porosity may be achieved by varying the velocity ofthe stream of the metal powder mixture through the nozzle during thecold spray process by controlling the temperature and gas pressure. Thecold spray deposit surface may have a certain amount of porosity, whichmay be generally uniform throughout. For example, the porosity may rangefrom about 5 to about 25% by volume (e.g., about 15%) as measured byASTM B962-08. The resulting exposed cold spray deposit surface may alsohave a surface topography that includes a generally uniform distributionof peaks and valleys, such as a topography by which there is betweenabout 25 μm and 50 μm from peak to valley.

Processing to form the interface preform (e.g., tile) may be undersuitable conditions for avoiding shrinkage of the preform duringsubsequent steps. That is, for instance, the continuous solid interfaceportion thus may be the result of employing a cohesive mass that isformed in situ with metal powder blocks (e.g., by a cold sprayingoperation) or is formed as a perform (e.g., a tile that is compacted,sintered, and/or cold sprayed). Though the cohesive mass is contemplatedto have some porosity, desirably the average size of any pores issufficiently small and the pores are substantially uniformly distributedso that voids would not result in irregular shrinkage in a consolidatedjoint following a final consolidating step to make a large area target.

The blocks may be contacted along their respective side edges (e.g., atleast partially along a length or a width of each block). It also may bepossible to stack two or more blocks. The contacted blocks areencapsulated in a pressing vessel, such as a suitable hot isostaticpressing container (e.g., a mild steel can that is hermetically sealedfor pressing). They are then hot isostatically pressed to a desiredshape at a temperature that is less than about 1100 or 1000° C. (e.g.,for molybdenum-containing materials and others) and at a pressure andfor a time sufficient to realize a consolidated joint between the firstand second blocks. A preferred approach may include a step of hotisostatically pressing a powder mass at a pressure of at least about 75MPa, or even at least about 100 MPa. A preferred approach may include astep of hot isostatically pressing a powder mass at a pressure of lessthan about 300 MPa, less than about 250 MPa, or even less than about 175MPa. The HIP process desirably may be performed and at a temperaturebelow about 1080° C. (e.g., about 1050° C.), below about 1000° C., belowabout 950° C., or even below about 900° C. (e.g., at about 890° C.). Assuch, the HIP process may be free of a step of heating the powder, thecan, or both to a temperature of about 1000° C. or higher. The HIPprocess may range in duration from about 1 to about 16 hours, and morepreferably about 3 to about 8 hours (e.g., about 4 hours). After thepressing is completed, the can may be removed. Following the hotisostatic pressing process, irregularities within the surface of anycold spray deposits are smoothed out, and there are no detectable pores.Other details about pressing operations can be gleaned from U.S. Pat.No. 7,837,929 ((Gaydos et al) incorporated by reference) (see e.g., theExamples).

In yet another aspect of the teachings herein, it is contemplated thatsputtering is performed using a sputtering target in accordance with thepresent teachings. It also is contemplated that thin films result thatare used in any of a number of electronic devices (e.g., as a barrierlayer, and electrode layer or both), such as one or more of television,a video display, a smartphone, a tablet computer, a personal digitalassistant, a navigation device, a sensor, a photovoltaic device, or aportable entertainment device (e.g., video players, music players,etc.).

The thin films may have a reduced amount of structural artifactsattributable to particles as compared with sputtering using targets withpowder joints, and are substantially uniform in structure (e.g., greaterthan about 98%). The thin films may have a thickness of less than about350 nm, less than about 225 nm, or even less than about 100 nm. The thinfilms may have a thickness of greater than about 5 nm, or even greaterthan about 10 nm. For example, the films may have a thickness of about15 to about 25 nm. The thin film may exhibit a resistivity value ofabout 70 to about 90, or even about 75 to about 85 μΩcm (using a fourpoint probe). The thin film may exhibit a 5B adhesion rating foradhesion to a substrate may of either Corning 1737 glass or amorphoussilicon (e.g., amorphous silicon coated glass per ASTM D:3359-02). Thethin film preferably exhibits good interfacing capability with copperconductors, such as copper conductive layers in display devices.

The targets herein may be made in a process that is free of any hotworking step, any forging step, or both. Though the temperatures for hotisostatic pressing preferably are below 1100° C., they may be about1100° C. or higher, or even 1200° C. or higher.

The teachings herein contemplate that resulting target body materialsinclude at least one pure metallic elemental phase, such as pure Mo (andmore preferably at least two pure metallic elemental phases, such aspore Mo and pure Ti), along with at least one alloy phase (e.g., β(Ti,Mo) phase). However, it is possible that the resulting target body willhave substantially no alloy phase, such as a β(Ti, Mo) phase (i.e.,about 15% (by volume) or less).

The microstructure of resulting target bodies preferably issubstantially uniform throughout the body. In a typical target body thatincludes molybdenum and at least one other element (e.g., Ti), themicrostructure preferably exhibits a matrix of pure molybdenum, withregions of the other element distributed substantially uniformlythroughout the matrix. Regions of the other element phase (e.g., puretitanium phase) are generally equiaxed. Regions of the other elementphase (e.g., pure titanium phase) may vary in size substantiallyuniformly throughout the body. For example, such regions may achieve alargest region diameter on the order of about 200 μm. Regions of thepure element phase (e.g., pure titanium phase) may have an averageregion diameter of out 50 to about 100 μm.

Bonding of adjoining blocks may take place along a side edge of a block,across a face of block, or both.

With reference to the drawings, FIG. 1 illustrates an example of a block10, having an upper surface 12 (which may be a sputtering surface in afinished target) and a side wall 14. The side wall 14 is shown having alayer of cold spray deposited powder on it. The powder may be delivered,via an apparatus (not shown) having a nozzle 16 through which a stream18 of a metal powder mixture is emitted while at a temperature (e.g.,about room temperature) below the atmospheric pressure meltingtemperature of any of the metals of the metal powder mixture. Two ormore blocks such as block 10 (each having a layer of cold sprayed powderdeposited in it) may thereafter be contacted with each other,encapsulated, and hot isostatically pressed as described herein.

FIG. 2 illustrates a tool 20 having a cavity 22 into which a stream 18of cold spray powder may be introduced to define a part that isgenerally complementary in shape with the shape of the cavity. In thismanner a preform (e.g., a tile) may be formed that will serve as acontinuous solid interface portion between opposing blocks.

FIG. 3 illustrates an example of the relative positions of a first block24, a second block 26 and interface preform (e.g., tile) 28 havingopposing joining surfaces 30 a and 30 b, in an assembly made inaccordance with the teachings herein. As can be appreciated in instanceswhen one or both of the blocks have cold spray deposited surface, suchas surface 14 of FIG. 1, the preform may be omitted. It is also possiblethat the preform may have a cold spray deposited side surface (e.g.,joining surfaces 30 a and/or 30 b of FIG. 3 may have a cold spraydeposited surface. The blocks 24 and 26 may be assembled together withthe interface preform between them, encapsulated, and hot isostaticallypressed as described herein.

As to all of the teachings herein, including those in the followingexamples, the volume percent of the respective phases are determined bya method that follows the principles from ASTM standards E562-11 andE1245-03 (2008). Following this method, an SEM backscatter detection(BSE) mode image is taken such that the phases are distinguishable bythe intensity of pixels in a black-and-white image. Using BSE mode, thenumber of scattered electrons will be directly related to atomic number,so heavier elements will appear brighter. For example, the largedifference in atomic number of Mo (42) and Ti (22) makes theidentification of each element possible from a backscatter image. Thealloy phase will typically appear gray, with an intensity betweenbrightest pure elemental (e.g., Mo) regions (showing as the most white)and the darkest pure elemental (e.g., Ti) regions, as illustrated inFIGS. 4a and 4b below. By analyzing a pixel intensity histogram (8-bitimage; intensities from 0-255), thresholds can be defined and the areapercentage of each phase can be calculated by a pixel count of theintensity range for each phase. Since the material is believed to besubstantially homogeneous with no preferred direction for any phase, thearea percentage is treated as being equal to the volume percentage ofeach phase. For the above analysis, the person skilled in the art willrecognize that it is possible that the thresholds may be defined in anobjective manner by measuring the minima between peaks in a pixelintensity histogram derived from the BSE image. For example, theseminima can be calculated by fitting a 2nd-order polynomial equation tothe histogram data at the regions between peaks.

By way of illustration, with reference to FIG. 4, there is showngenerally an illustrative microstructure that may be expected for aMo—Ti target body prepared by hot isostatic pressing of a metal powdermixture having about 50 at % Mo and 50 at % Ti. In these scanningelectron microscope images (in backscatter electron detection mode), thepure titanium phase is the darkest phase. The medium shaded phaseessentially surrounding the titanium is a titanium/molybdenum alloyphase (e.g., believed to be a β-phase, but which has varyingconcentrations of titanium and molybdenum throughout), and the lightestphase is molybdenum. For the embodiment of FIG. 4, there is seen to be avolume percentage of β-phase of about 55.7 vol %, about 39.6 vol % Moand about 4.7 vol % Ti.

As seen from the above, an approach to the formation of large areasputtering targets is provided. The approach is predicated generallyupon the avoidance of joining consolidated blocks using (as the primaryor main joinder mechanism) diffusion bonding via hot isostatic pressingof a loose powder between the blocks. The present teachings envisionemploying a continuous solid interface portion as an intermediate layerbetween the blocks. The continuous solid interface portion may be madeby (a) cold spraying at least one metal powder onto at least one of theblocks for forming the at least one continuous solid interface portion;(b) compacting a body of a metal powder mixture to form the at least onecontinuous solid interface portion; (c) sintering a body of a metalpowder mixture to form the at least one continuous solid interfaceportion; (d) cold spraying at least one metal powder into a die formingthe at least one at least one continuous solid interface portion; (e)cold spraying a metal powder onto a substrate to form the at least onecontinuous solid interface portion that may optionally include, butpreferably omits, the substrate; or (f) any combination of (a) through(e). It should be appreciated that reference to “continuous solidinterface portion” does not require that such portion be free of anyporosity. As the teachings indicate, some porosity is to be expected(e.g., prior to a final hot isostatic pressing operation, the density ofany of the described continuous solid interface portions may be at leastabout 60%, 70%, 80% or higher). Desirably, during any steps of makingthe continuous solid interface portion starting powders of two or more,though mixed together, remain unalloyed, and may not become alloyeduntil a subsequent hot isostatic pressing operation.

The present teachings are illustrated by reference to sputtering targetsthat include molybdenum with one or more other elements. The teachingsmay also be applicable to materials as well, and are not necessarilylimited to molybdenum-containing systems. For example, other refractorymetals (e.g., tungsten, niobium, tantalum or any combination thereof)may be employed in a major amount (at % vol % or wt %) of the target.The present teachings may be employed as an alternative for bondingadjoining blocks that include two discontinuous phases and/or thatheretofore require explosive bonding techniques. By way of example,without limitation, Ta/Ta-2.5W clad plates may be joined using thetechniques herein. Further, though the teachings herein are particularlyapplicable to on consolidated powder metallurgy derived target blocks,they can also be employed to join cast or ingot-derived blocks (e.g.,electron beam melted and thermomechanically processed blocks).

One benefit of the teachings herein is believed due to the avoidance ofpotential issues with segregation, low density, and/or shrinkage, whichare often associated with hot isostatic pressing diffusion bonding withthe use of a powder for defining an interlayer. Without intending to bebound by theory, the conditions taught herein are selected to that thereis an enhanced driving force for atomic transport from the solidinterface portion during a final consolidation step due to the reductionin surface energy (and perhaps strain energy) to the interface, which inturn helps to enhance bonding. These mechanisms are not believed toexist using other techniques in the published literature, and arebelieved to result in a consolidated interface portion that ischemically, metallurgically, and visually substantiallyindistinguishable from the bulk material in the blocks.

As to all of the foregoing general teachings, as used herein, unlessotherwise stated, the teachings envision that any member of a genus(list) may be excluded from the genus; and/or, any member of a Markushgrouping may be excluded from the grouping. Percentages of thesputtering target expressed herein refer to the material of thesputtering Percentages of the sputtering target expressed herein referto the material of the sputtering target available for sputterdeposition, and do not include other sputter target components, such asbacking plates.

Unless otherwise stated, any numerical values recited herein include allvalues from the lower value to the upper value in increments of one unitprovided that there is a separation of at least 2 units between anylower value and any higher value. As an example, if it is stated thatthe amount of a component, a property, or a value of a process variablesuch as, for example, temperature, pressure, time and the like is, forexample, from 1 to 90, preferably from 20 to 80, more preferably from 30to 70, it is intended that intermediate range values such as (forexample, 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc.) are within theteachings of this specification. Likewise, individual intermediatevalues are also within the present teachings. For values which are lessthan one, one unit is considered to be 0.0001, 0.001, 0.01 or 0.1 asappropriate. These are only examples of what is specifically intendedand all possible combinations of numerical values between the lowestvalue and the highest value enumerated are to be considered to beexpressly stated in this application in a similar manner. As can beseen, the teaching of amounts expressed as “parts by weight” herein alsocontemplates the same ranges expressed in terms of percent by weight.Thus, an expression in the Detailed Description of a range in terms ofat “‘x’ parts by weight of the resulting polymeric blend composition”also contemplates a teaching of ranges of the same recited amount of “x”in percent by weight of the resulting composition.

Unless otherwise stated, all ranges include both endpoints and allnumbers between the endpoints. The use of “about” or “approximately” inconnection with a range applies to both ends of the range. Thus, “about20 to 30” is intended to cover “about 20 to about 30”, inclusive of atleast the specified endpoints. Concentrations of ingredients identifiedin Tables herein may vary ±10%, or even 20% or more and remain withinthe teachings.

The disclosures of all articles and references, including patentapplications and publications, are incorporated by reference for allpurposes. The term “consisting essentially of” to describe a combinationshall include the elements, ingredients, components or steps identified,and such other elements ingredients, components or steps that do notmaterially affect the basic and novel characteristics of thecombination. The use of the terms “comprising” or “including” todescribe combinations of elements, ingredients, components or stepsherein also contemplates embodiments that consist essentially of, oreven consist of the elements, ingredients, components or steps. Pluralelements, ingredients, components or steps can be provided by a singleintegrated element, ingredient, component or step. Alternatively, asingle integrated element, ingredient, component or step might bedivided into separate plural elements, ingredients, components or steps.The disclosure of “a” or “one” to describe an element, ingredient,component or step is net intended to foreclose additional elements,ingredients, components or steps. All references herein to elements ormetals belonging to certain Group refer to the Periodic Table of theElements published and copyrighted by CRC Press, Inc., 1989. Anyreference to the Group or Groups shall be to the Group or Groups asreflected in this Periodic Table of the Elements using the IUPAC systemfor numbering groups. It is understood that the above description isintended to be illustrative and not restrictive. Many embodiments aswell as many applications besides the examples provided will be apparentto those of skill in the art upon reading the above description. Thescope of the invention should, therefore, be determined not withreference to the above description, but should instead be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled. The disclosures of allarticles and references, including patent applications and publications,are incorporated by reference for all purposes. The emission in thefollowing claims of any aspect of subject matter that is disclosedherein is not a disclaimer of such subject matter, nor should it beregarded that the inventors did not consider such subject matter to bepart of the disclosed inventive subject matter.

What is claimed is:
 1. A method for making a sputtering target,comprising the steps of: a. providing first and second at leastpartially consolidated powder metal blocks each having a preparedsurface, and each including an alloy including molybdenum in an amountgreater than about 30 percent by weight and at least one additionalalloying element; b. interposing between the consolidated powder metalblocks at least one continuous solid interface portion; c. contactingthe prepared surface of the first block indirectly with the preparedsurface of the second block via the at least one continuous solidinterface portion in the substantial absence of any loose powder bondingagent between contacted surfaces to form a contacted joint structure; d.isostatically pressing the contacted structure at a temperature that isless than about 1080° C. at a pressure and for a time sufficient torealize a consolidated joint between the first and second blocks;wherein the interposing step includes a step selected from (i) coldspraying a metal powder onto at least one of the blocks for forming theat least one continuous solid interface portion; (ii) compacting a bodyof metal powder to form the at least one continuous solid interfaceportion; (iii) sintering a body of a metal powder mixture to form the atleast one continuous solid interface portion; (iv) cold spraying a metalpowder into a die for forming the at least one continuous solidinterface portion; (v) cold spraying a metal powder onto a substrate toform the at least one continuous solid interface portion that mayinclude or omit the substrate; or (vi) any combination of (i) through(v).
 2. The method of claim 1, wherein the step of providing includes astep of forming the first and second blocks from an alloy that includesmolybdenum, and at least one alloying element selected from titanium,chromium, niobium, tantalum, tungsten, zirconium or any combinationthereof.
 3. The method of claim 1, wherein the step of isostaticallypressing includes pressing at a temperature between about 500 and about1080° C. while the contacted structure is encapsulated in a sealedvessel.
 4. The method of claim 3, wherein the step of isostaticallypressing includes pressing at a pressure of at least about 70 MPa whilethe contacted structure is encapsulated in a sealed vessel.
 5. Themethod of claim 1, wherein the step of isostatically pressing includesmaintaining a pressure of about 80 to about 140 MPa at a temperature ofabout 700° C. to about 1080° C. for a time of about one to about sixhours while the contacted structure is encapsulated in a sealed vessel.6. The method of claim 5, wherein the at least one alloying element istitanium; and the step of isostatically pressing is performed underconditions sufficient so that a microstructure is realized that ischaracterized as including a pure titanium phase, a pure molybdenumphase and an alloy phase of titanium and molybdenum.
 7. The method claim6, wherein the step of isostatically pressing is performed underconditions sufficient so that the resulting consolidated joint providesa structure that has a transverse rupture strength per ASTM B528-10, ofat least about 620 MPa.
 8. The method of claim 7, wherein a resultingoxygen weight concentration of the blocks of the sputtering target isbetween about 1000 ppm and 3500 ppm.
 9. The method of claim 1, whereinthe resulting sputtering target includes at least one continuous solidinterface portion derived from a cold spray deposition, a sinteredpreform body, a compacted powder body or any combination thereof; and ajoint between the at least partially consolidated blocks, which joinsthe blocks together to define a target body, the joint including the atleast one continuous solid interface portion, wherein the sputteringtarget along the joint exhibits a transverse rupture strength per ASTMB528-10, of at least about 600 MPa.
 10. The method of claim 1, whereinthe first and second at least partially consolidated powder metal blocksare formed from powder that is first compacted to about 60 to about 85%of theoretical density and then further densified prior to forming thejoint; and the joint exhibits a transverse rupture strength per ASTMB528-10, of at least 600 MPa.
 11. The method of claim 10, wherein theresulting sputtering target includes a target body defined by theconsolidated powder metal blocks and the joint formed from thecontinuous solid interface portion, wherein throughout the target bodythere is a substantially continuous and uniform distribution of threephases including a substantially pure molybdenum phase, a substantiallypure phase of the at least one additional alloying element and a thirdphase that includes an alloy of molybdenum and the at least oneadditional alloying element.
 12. The method of claim 11, wherein the atleast one additional alloying element includes titanium.
 13. The methodof claim 12, wherein the amount of the substantially pure molybdenumphase is about 30 to about 60 vol % of the sputtering target body. 14.The method of claim 13, wherein the amount of the substantially purephase of the at least one additional alloying element is about 5 toabout 25 vol %.
 15. The method of claim 14, wherein the alloy ofmolybdenum and the at least one additional alloying element includes aβ-phase of molybdenum and titanium, in an amount greater than about 40vol % of the alloy, of the target, or both.
 16. The process of claim 1,wherein the resulting sputtering target comprises: a. the at least twoconsolidated blocks; b. the at least one continuous solid interfaceportion; and c. a joint between the at least two consolidated blocks,which joins the blocks together to define a target body, the jointincluding the at least one continuous solid interface portion, whereinthe resulting sputtering target along the joint exhibits a transverserupture strength per ASTM B528-10, of at least about 400 MPa.
 17. Amethod for making a sputtering target, comprising the steps of: a)providing first and second at least partially consolidated powder metalblocks each optionally having a prepared surface, and each including analloy including a refractory metal in an amount greater than 30 percentby weight and at least one additional alloying element; b) interposingbetween the consolidated powder metal blocks at least one continuoussolid interface portion, wherein the continuous solid interface portionis derived from a cold spray deposition onto a surface of at least oneof the consolidated powder metal blocks, wherein the cold spraydeposition has a porosity from 5 to 25% by volume as measured by ASTMB962-08 prior to the formation of the joint; c) contacting the preparedsurface of the first consolidated powder metal block indirectly with theprepared surface of the second consolidated powder metal block via theat least one continuous solid interface portion in the substantialabsence of any bonding agent between the contacted surfaces to form acontacted joint structure; and d) isostatically pressing the contactedstructure at a temperature that is less than 1080° C. at a pressure andfor a time sufficient to realize a consolidated joint between the firstand second consolidated powder metal blocks.
 18. The method of claim 17,wherein the first and second at least partially consolidated powdermetal blocks are formed from powder that is first compacted to about 60to about 85% of theoretical density and then further densified prior toforming the joint; the resulting sputtering target includes a targetbody defined by the consolidated powder metal blocks and the jointformed from the continuous solid interface portion, wherein throughoutthe target body there is a substantially continuous and uniformdistribution of three phases including a substantially pure molybdenumphase, a substantially pure phase of the at least one additionalalloying element and a third phase that includes an alloy of molybdenumand the at least one additional alloying element; and the at least onealloying element includes titanium, chromium, niobium, tantalum,tungsten, zirconium or any combination thereof.
 19. The method of claim18, wherein the at least one additional alloying element includestitanium; the amount of the substantially pure molybdenum phase is about30 to about 60 vol % of the sputtering target body; the amount of thesubstantially pure phase of the at least one additional alloying elementis about 5 to about 25 vol %; and the alloy of molybdenum and the atleast one additional alloying element includes a 8-phase of molybdenumand titanium, in an amount greater than about 40 vol % of the alloy, ofthe target, or both.
 20. The method of claim 19, wherein the jointexhibits a transverse rupture strength of at least 600 MPa as measuredaccording to ASTM B528-10.
 21. A method for making a sputtering target,comprising the steps of: a. providing first and second at leastpartially consolidated powder metal blocks each having a preparedsurface, and each including an alloy including molybdenum in an amountgreater than about 30 percent by weight and at least one additionalalloying element; b. interposing between the consolidated powder metalblocks at least one continuous solid interface portion; c. contactingthe prepared surface of the first block indirectly with the preparedsurface of the second block via the at least one continuous solidinterface portion in the substantial absence of any loose powder bondingagent between contacted surfaces to form a contacted joint structure; d.isostatically pressing the contacted structure at a temperature that isless than about 1080° C. at a pressure and for a time sufficient torealize a consolidated joint between the first and second blocks;wherein the continuous solid interface portion is i) a cold spraydeposition having a porosity of 5 to 25% by volume as measured by ASTMB962-08 prior to the step of isostatically pressing the contactedstructure; or ii) a tile having a density of 60% to 85% of theoreticaldensity prior to the step of isostatically pressing the contactedstructure.
 22. The method of claim 21, wherein the continuous solidinterface portion is a cold spray deposition having a porosity of 5 to25% by volume as measured by ASTM B962-08 prior to the step ofisostatically pressing the contacted structure.
 23. The method of claim21, wherein the continuous solid interface portion is a tile having adensity of 60% to 85% of theoretical density prior to the step ofisostatically pressing the contacted structure.